Need to vent

Brittney
My boyfriend has been having tooth pain for a month and he's gone to the ER multiple times for pain management and antibiotics. This last visit they told him he had an exposed nerve and now he's desperately been wanting to get the teeth extracted. I have been looking for somewhere that will take emergencies without insurance and found that a hospital in the city takes emergency dental walk-ins but only until 1pm. Now he wants me to leave work and rush to get him there because I'm the only one with a car and license. I babysit my nephews as work and this morning the three year old woke up with his ear hurting so his mom took him to a rapid care clinic (he does have an ear infection). When I called she said it was packed but that I could go as soon as she returned. Now my bf is pissed off at me because she won't be home in time for me to bring him and is demanding I call her and tell her she needs to be here. I told him my nephew has an ear infection and is at the doctors but he does not care. He doesn't get along with my SIL and thinks that she will purposely be late. I just don't know what he expects? I get that he's been in pain but I can't just up and leave. It's stressing me out because now I know when I go home he will be mad and probably not tak to me or something. 
UPDATE: He just called me screaming asking if I was home or not. Literally shouting at me through the phone and I have no idea why.